1. Field of the Invention
This invention relates to an ophthalmic irrigation and aspiration system and, more particularly, to venting in an ophthalmic aspiration system.
2. Related Art
All ophthalmic irrigation and aspiration systems currently on the market provide only one means for venting. The term "venting" refers to the common practice of reducing or eliminating a vacuum or pressure differential between components of an irrigation/aspiration system, or between the irrigation/aspiration system and ambient atmosphere pressure.
The term "fluid venting" refers to the reduction of pressure differentials between the portion of the aspiration circuit that contacts the eye and remainder of the aspiration circuit by way of a connection between the irrigation fluid path and the aspiration path. The term "air venting" or "atmospheric venting" refers to the reduction of pressure differentials between the portion of the aspiration circuit that contacts the eye and remainder of the aspiration circuit by way of a connection between the aspiration path and ambient air at atmospheric pressure.
In ophthalmic irrigation/aspiration systems that utilize a peristaltic pump, fluid venting is the most commonly used method. For example, the Legacy microsurgical system sold by Alcon Laboratories uses fluid venting in its peristaltic-pump-based irrigation/aspiration system. No other type of venting is utilized in this system.
In some peristaltic systems, such as that commercialized by AMO, venting is accomplished through pump reversal.
For venturi aspiration systems, such as that commercialized by Bausch & Lomb Surgical in its Phacotron Gold product and in its Storz Millennium Microsurgical System product, air venting is used.
All ophthalmic aspiration systems currently in commercial use have a single method or option for venting with no opportunity for selection.
Accordingly, there is a need in the art to provide an ophthalmic aspiration system that provides the ability to select, either manually or automatically, among or between various methods of venting in an ophthalmic aspiration system.